The operation of escalators, and particularly the handrails of escalators, is well-known in the art. Generally, the motion of a handrail of an escalator is driven by connecting the main drive of the escalator to a friction wheel coupled to the handrail.
In some situations, for example in escalators of great length or steep incline, a single friction wheel driven by the main drive motor is insufficient to overcome the handrail friction and drive the handrail. In these situations, a second friction wheel, driven by a separate handrail motor, is used. However, these systems are often difficult to control. The speed required of the handrail motor depends greatly on the length and incline of the escalator. Any change to these parameters requires extensive reconfiguration. A closed-loop control system could be used to address such changes, but closed-loop systems are often expensive to implement, requiring additional hardware.